Lever and fulcrum pin arrangement for a control device or the like



Aug. 19, 1969 Filed Oct. 17. 1967 R. c. DEM] v 3,462,079 LEVER AND FULCRUM PIN ARRANGEMENT FOR A CONTROL DEVICE OR THE LIKE I 2 Sheets-Sheet 1 FIG'.'4

INVENTOR ROY C. DEM! .HIS ATTORNEYS Aug. 19, 1969 R. 0. new 3. 62,079

' LEVER AND FULCRUM PIN ARRANGEMENT FOR A CONTROL DEVICE OR THE LIKE Filed Oct. '17, 1967 2 Sheets-Sheet 2 46 D SL569 ia /h #67:

FIG] INVENTOR ROY C. DEMI rus ATTORQEYS United States Patent LEVER AND FULCRUM PIN ARRANGEMENT FOR A CONTROL DEVICE OR THE LIKE Roy C. Demi, Greensburg, Pa., assignor to Robertshaw Controls Company, Richmond, Va., a corporation of Delaware Filed Oct. 17, 1967, Ser. No. 675,836 Int. Cl. G05d 23/12; F16k 31/44; G05g 1/04 U.S. Cl. 23699 11 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a control device having a valve member that is moved relative to its valve seat in response to a temperature sensing device, the valve member being operated by a lever having an intermediate portion thereof fulcrumed on an end means of an adjustable fulcrum pin that has its position adjusted by a control knob setting of the control device whereby the temperature sensing device acts on one end of the lever and the other end of the lever acts on the valve member. The fulcrum pin has a transversely disposed rod at the fulcrum end thereof and the fulcruming portion of the lever is so constructed and arranged that only the opposed sides of the lever engage against the opposed ends of the rod to provide a stable arrangement allowing for more mispositioning of the parts of the control device before the lever will be upset on the fulcrum pin.

This invention relates to an improved fulcrum pin and lever arrangement for a control device as well as to improved parts for such a fulcrum pin and lever arrangement.

It is well known from the United States patent to Tyler, No. 3,341,119, that a control device can be provided wherein a lever is fulcrumed at an intermediate portion thereof on an axially adjustable fulcrum pin whereby a temperature responsive device can act on one end of the lever and a spring means can act on the other end of the lever to cause the lever to follow the movement of the temperature responsive device and have the other end of the lever operate a valve member of the control device that controls the flow of fuel to the burner means of a cooking apparatus.

However, according to the teachings of this invention. it has been found that such prior known lever and fulcrum pin arrangement requires the plane of the lever to be dependent upon a small diameter shoulder face of the diaphragm stud of the temperature responsive element as well as the ball end of the fulcrum pin whereby the attitude of the lever spring force to the lever was very critical. Accordingly, any moment of the spring force applied other than perpendicular to the common center line of the lever tended to rotate the lever about the ball and socket fulcrum pin end to cause unseating at the diaphragm stud of the thermostatic element whereby a calibration shift in the control device resulted if and when such rotation occurred. Thus, the control device'would not maintain the desired temperature effect of the burner means being controlled thereby. 7

Such problem has been substantially eliminated by the features of this invention.

In particular, the lever and fulcrum pin arrangement of this invention can have the spring force applied at the valve operating end of the lever in a relatively wide area without causing an adverse unseating of the other end of the lever at the diaphragm stud of the temperature responsive element.

For example, one embodiment of this invention provides a fulcrum pin or packing pin carrying a transversely 3,462,079 Patented Aug. 19, 1969 ICC disposed rod or groove pin at one end means of the fulcrum pin whereby the opposed ends of the rod extend beyond opposed sides of the fulcrum pin. The lever of this invention has an inverted substantially U-shaped groove disposed transversely across an intermediate portion of the lever with that intermediate portion having a substantially V-shaped transverse cross-sectional configuration at the apex of the U-shaped configuration thereof whereby only the opposed sides of the lever at the intermediate portion thereof engage against the opposed ends of the rod of the fulcrum pin to provide the fulcruming means for the lever.

Accordingly, it is an object of this invention to provide an improved control device having one or more of the novel features set forth above or hereinafter shown or described.

Another object of this invention is to provide an improved fulcrum pin means for such a control device or the like.

A further object of this invention is to provide an improved lever for such a control device or the like.

Other objects, uses and advantages of this invention are apparent from a reading of this description, which proceeds with reference to the accompanying drawings forming a part thereof and wherein:

FIGURE 1 is a cross-sectional view of a control device utilizing the features of this invention.

FIGURE 2 is an exploded perspective view of the fulcrum pin means and lever of the control device of FIGURE 1.

FIGURE 3 is an enlarged view of the rod member for the fulcrum pin of this invention.

FIGURE 4 is a cross-sectional view taken on line 4-4 of FIGURE 3.

FIGURE 5 is an enlarged, fragmentary view of the assembled lever and fulcrum pin of this invention.

FIGURE 6 is a cross-sectional view taken substantially on line 66 of FIGURE 5.

FIGURE 7 is a schematic view illustrating the various pivot points of the lever of this invention in comparison with the prior known lever means.

While the various features of this invention are hereinafter described as being particularly adaptable for providing a lever and fulcrum pin arrangement for a fuel supplying control device or the like, it is to be understood that the various features of this invention can be utilized singly or in any combination thereof to provide fulcrum arrangements or parts for other devices as desired.

Therefore, this invention is not to be limited to only the embodiment illustrated in the drawings, because the drawings are merely utilized to illustrate one of the wide variety of uses of this invention.

Referring now to FIGURE 1, the improved control device of this invention is generally indicated by the reference numeral 10 and is similar in operation to the control device fully set forth in the aforementioned patent to Tyler, No. 3,341,119, except for the improvements in the lever and fulcrum pin arrangement thereof as will be apparent hereinafter whereby only the details of the control device 10 that are necessary to fully understand this invention will be described and the other details of the parts and operation of the control device 10 illustrated in the drawings can be understood by referring to the aforementioned U.S. patent to Tyler.

In particular, the control device 10 includes a housing means 11 having an outlet passage means 12 to be interconnected to a source of fuel when a groove means 13 of a rotatable disc valve member 14 aligns the fuel supply to the outlet 12 upon the operator turning the selector knob 15 to an on position thereof. Such rotation of the selector knob 15 causes a threaded member 16 to be axially adjusted relative to the housing 14 whereby the free end 17 of a calibration screw 18 carried by the threaded member 16 will be likewise axially adjusted relative to the housing 11.

The housing 11 carries an axially movable fulcrum pin 19 of this invention in a bore means 20 thereof whereby one end 21 of the pin 19 is disposed in engagement with the end 17 of the adjusting screw 18 to follow the movement thereof while the other end means 22 of the fulcrum pin 19 provides a fulcrum point means for a lever 23 of this invention in a manner hereinafter described.

The lever 23 has one end 24 engaging against a stud 25 of a movable wall or diaphragm 26 of a power element 27 that is carried by the housing 11 and expands and contracts in relation to the temperature sensed by a temperature sensing bulb 28 fluidly interconnected to the interior of the power element 27 by a capillary tube 29.

A compression spring 30 is carried by the housing 11 and has one end 31 bearing against the housing 11 and the other end 32 thereof bearing against the other end means 33 of the lever 23 to cause an intermediate portion 34 of the lever 23 to fulcrum against the end means 22 of the fulcrum pin 19 in a manner hereinafter described and cause the other end 24 of the lever 23 to follow the movement of the movable wall 26 of the power element 27 relative to the housing 11.

A valve seat member 35 is carried by the housing 11 and has a valve seat 36 opened and closed by a valve member 37 normally urged to its closed position by a compression spring 38. A valve actuating pin 39 is carried by the valve seat member 35 and has One end 40 en'gageable against the end 3-3 of the lever 23 while the other end 41 engages against the valve member 38.

Suitable passage means 42 are formed in the housing means 11 to interconnect the fuel outlet passage 12 with the valve seat 36 so that when the valve seat 36 is opened in a manner hereinafter described, the fuel outlet passage 12 is interconnected to a chamber 43 of the housing 11 that leads to a pilot burner means (not shown) of the cooking apparatus containing the control device so that when the fuel issuing from the pilot burner means is subsequently ignited, suitable flame sensing means (not shown) will effectively interconnect the fuel outlet passage 12 directly to the main burner means of the cooking apparatus. Therefore, as long as the valve member 37 is moved to an open position, the control device 10* will continuously supply fuel to the main burner means. How ever, when the temperature effect of the main burner means reaches the temperature setting of the control knob 15, the control device closes the valve member 37 against the valve seat 36 to terminate the supply of fuel to the pilot burner whereby the flame sensing means detects that a flame no longer exists at the pilot burner means and will prevent the main source of fuel from the fuel outlet 12 from reaching the main burner means until the pilot burner means is again supplied fuel by the temperature sensing device 28 causing the valve member 37 to again move away from the valve seat 36.

Thus, it can be seen that when the control knob of the control device 10 is rotated to a temperature setting position thereof, the fulcrum pin 19 is axially adjusted relative to the housing 11 by moving further to the right in FIGURE 1 as the temperature setting of the knob 15 progressively increases whereby the compression spring 30 causes the lever 23 to follow such movement of the pin 19 and open the valve member 37 in opposition to the force of the compression spring 38 as long as the temperature sensing device 28 is sensing a temperature below the temperature setting of the control knob 15.

Subsequently, as the temperature effect of the cooking apparatus increases, the movable wall 26 of the power element 27 progressively moves to the right in FIGURE 1 to cause the end 33 of the lever 23 to progressively move in a counterclockwise direction in FIGURE 1 so that when the selected temperature is reached, the end 33 of the lever 23 has moved in a counterclockwise direction in opposition to the force of the compression spring 30 a distance sufiicient to permit the valve member 37 to close against the valve seat 36 and thereby terminate the operation of the main burner means of the cooking apparatus. Thereafter, when the temperature efiect of the cooking apparatus falls below the selected temperature, the movable wall 26 of the power element 27 again moves back toward the left in FIGURE 1 permitting the end 33 of the lever 23 to begin moving in a clockwise direction in FIGURE 1 to open the valve member 37.

Therefore, it can be seen that the control device 10 operates in such a manner that the main burner means will be cycled on and olf by the opening and closing of the valve member 37 that is operated by the power element 27 acting on the lever 23 that is fulcrumed on the axially adjustable fulcrum pin 19.

The particular details of the lever 23 and fulcrum pin 19 of this invention will now be described and reference is made to FIGURES 2-7 of the drawings fully illustrating such lever 23 and fulcrum pin 19.

As illustrated in FIGURES 2, 5 and 6, the fulcrum pin 19 has a reduced cylindrical part 44 at the end means 22 thereof, the reduced part 44 having a substantially cylindrical bore 45 passing transversely therethrough and receiving a cylindrical rod 46 that has the opposed ends 47 and 48 thereof respectively extending beyond the opposed sides of the projecting portion 44 of the fulcrum pin 19 as fully illustrated in FIGURES 2 and 6.

While the rod 46 can be secured in the bore 45 of the fulcrum pin 19 in any suitable manner, the rod 46 illustrated in the drawings is press fitted in the bore 45 to secure the rod 46 to the fulcrum pin 19 in the assembled relationship illustrated in FIGURE 6. For example, the rod 46 as illustrated in FIGURES 3 and 4 has the intermediate portion 49 thereof externally staked or indented at points 50 to enlarge the intermediate portion 49 thereof to permit the same to be press fitted in the bore 45 ofthe fulcrum pin 19 to secure the same thereto, three such equally spaced staking points 50 being illustrated in the drawings.

The lever 23 of this invention as illustrated in FIG- URES 2, 5 and 6 has outwardly directed tangs 51 carved at the opposed side edges 52 and 53 thereof to hold the end 32 of the compression spring 30 therebetween.

The other end 24 of the lever 23 has an opening 54 passing therethrough and is staked at the opposed sides of the opening 54 to define outwardly directed projections 55 which will bear against the diaphragm stud 25 of the power element 27, the opening 54 in the end 24 of the lever 23 permitting an extension 56 of the power element 27 to pass therethrough and carry a valve member 57 for opening and closing a valve seat 58 in the fuel outlet passage 12 in order to provide a high limit temperature safety feature to control or cut off the flow of fuel to the main burner means should a runaway temperature condition exist whereby such high limit valve means 57 does not form part of this invention and further details thereof can be made by reference to the aforementioned US. patent to Tyler.

The intermediate portion 34 of the lever 23 has a substantially inverted U-shaped groove 59 provided therein that extends from one side edge 52 thereof to the other side edge 53 thereof as illustrated in FIGURE 2 and 5. The groove 59 is so constructed and arranged that the same has a substantially inverted V-shaped transverse cross-sectional configuration at the apex thereof as illustrated in FIGURE 6 between the side edges 52 and 53 of the lever 23. In addition, the lever 23 has an elongated opening 60 passing through the longitudinal axis or centerline thereof at the apex of the groove 59 whereby the long dimension of the opening 60 is along the longitudinal axis of the lever 23 for a purpose hereinafter described.

The longitudinal ends of the groove 59 as illustrated in FIGURE 5 of the lever 23 define an included angle of approximately 90 degrees between the surfaces 61 and 62 at each opposed side edge 52 and 53 of the lever 23 whereas the groove 59 is relieved by an angle of approximately 6 deg-recs relative to the horizontal from each side 52 and 53 of the lever toward the center thereof as represented respectively by the surfaces 64 and 65 in FIGURES 6.

Thus, it can be seen that when the lever 23 is assembled to the end means 22 of the fulcrum pin 19 in the manner illustrated in FIGURES l, 5 and 6, the 'portion 44 of the fulcrurm pin 19 projects through the opening 60 of the lever 23 whereby the opposed sides or edges 52 and 53 of the lever 23 respectively engage against the opposed ends 47 and 48 of the rod 46 at points .66 and 67 as illustrated in FIGURE 5 so that the lever 23 will only fulcrum against the rod 46 at the extreme outer side edges 52 and 53 of the lever 23 because of the aforementioned transverse V-shaped cross-sectional configuration of the groove 59 defined by the angled surfaces 64 and 65 of FIGURE 6.

In this manner, when the assembled fulcrum pin 19 and lever 23 are disposed in the housing 11 of the control device 10, the compression spring 30 acting on the end 33 of the lever 23 maintains the side edges 52 and 53 of the lever 23 in engagement with the opposed ends 47 and 48 of the rod 46 while engaging the projections 55 on the end 24 of the lever 23 against the diaphragm stud 25 of the power element 27 to cause the end 24 of the lever 23 to follow the movement of the stud 25 while fulcruming on the fulcrum pin 19. The elongate opening 60 in the lever 23 permits full pivoting movement of the lever 23 on the rod 46 without interference with the projecting part 44 of the fulcrum pin 19.

Since the fulcrum pin 19 is substantially free to rotate in the bore 30 of the housing 11 of the control device 10, the fulcrum pin 19 and its interconnected rod 46 are thus free to rotate in the housing 11 relative to the lever 23 to a point where the center line of the rod 46 is 90 degrees to the longitudinal center line of the lever 23. Since the apex 68 of the groove 59 in the lever 23 defined between the surfaces 61 and 62 thereof that provides the aforementioned included angle of approximately 90 degrees has a permissible radius less than the radius of the rod 46, it can be seen that the lever 23 in its assembled relationship with the fulcrum pin 19 in the control device comes to rest on the rod 46 only at the outside edges or sides 52 and 53 of the lever 23 represented by the reference numerals 66 and 67 in FIGURE 5 because of the aforementioned 6 degree relief in the transverse direction of FIGURE 6 defined by the surfaces 64 and 65. The 6 degree relief also insures suflicient clearance between the lever 23 and the barbs or expanded portions of the intermediate part 49 of the rod 46 utilized for the aforementioned press fit relation with the bore 45 of the fulcrum pin 19.

The improved results of the lever 23 and fulcrum pin 19 of this invention over the lever and fulcrum pin arrangement disclosed in the aforementioned U.S. patent to Tyler is schematically illustrated in FIGURE 7 and will now be described.

As illustrated in FIGURE 7, the lever 23 of this invention is represented in substantially rectangular form and the horizontal line 69 represents the fulcrum area provided by the fulcrum pin means while the horizontal line 70 represents the area that the compression spring 30 will impose a force on the end 33 of the lever 23 in its assembled relation in the control device 10. The circle 71 represents the area that the diaphragm stud 25 of the power element 27 will impose a force against the end 24 of the lever 23 as provided by the outwardly directed projections 55 of the lever 23 as illustrated in FIGURE 2.

Since the lever of the device disclosed in the U.S. patent to Tyler fulcrums on a ball end of a fulcrum pin substantially at the point A where the horizontal line 69 crosses the longitudinal axis or center line 72 of the lever, the spring force of the compression spring 30 must act on the end 33 of the lever between the points B and C on the horizontal line 70 where the lines 73 and 74 respectively extend from opposed sides of the circle 71 and cross at the fulcrum point A.

However, when utilizing the features of this invention, it can be seen that since the lever 23 fulcrurns on the fulcrum pin means 19 only at the outer sides edges 52 and 53 thereof as represented by the points D and E in FIGURE 7, then the spring force of the compression spring 30 can be applied against the end 33 of the lever 23 of this invention anywhere along the horizontal line 70 between the points F and'G respectively determined by where the lines 75 and 76 cross the horizontal line 70 and respectively pass through the pivot points D and E and tangent points on opposed sides of the circle 71.

Therefore, it can be seen that the spring force of the compression spring 30 of the control device 10 can vary over a very broad tolerance range as represented by length of the line 70 between the points F and G of FIGURE 7 before such spring force will upset the plane of the lever 23 and cause calibration error in the control device 10. In contrast thereto, it can be seen that the spring force of the lever arrangement disclosed in the U.S. patent to Tyler can only vary within a very narrow tolerance range as represented by the length of the line 70 between the points B and C of FIGURE 7 before the spring force will upset the plane of the lever and cause such calibration error of the control device.

Therefore, it can be seen that this invention not only provides an improved control device, but also this invention provides improved parts for a lever and fulcrum pin arrangement of such a control device or the like.

While the form of the invention now preferred has been disclosed as required by the statutes, other forms may be used, all coming within the scope of the claims which follow.

What is claimed is:

1. In combination, a housing means having an inlet and an outlet interconnected together by a valve seat, a movable valve member for opening and closing said valve seat, a lever having one end for moving said valve member relative to said valve seat, an axially movable pin carried by said housing means and having one end means fulcruming said lever intermediate the ends of said lever, and manipulator means carried by said housing means and having one end engaging the other end of said pin whereby said manipulator means adjusts the axial position of said pin along its longitudinal axis relative to said housing means, said one end means of said pin including a fulcrum member disposed transversely to said longitudinal axis of said pin and against which said lever engages to fulcrum thereon, said fulcrum member having opposed ends extending in opposite directions from and transversely to said longitudinal axis of said pin, said lever having opposed side edges and engaging said opposed ends of said fulcrum member only at said opposed side edges of said lever.

2. A combination as set forth in claim 1 wherein a temperature responsive device is carried by said housing means and engages the other end of said lever.

3. A combination as set forth in claim 1 wherein spring means is carried by said housing means and engages said one end of said lever to tend to open said valve member.

4. A combination as set forth in claim 1 wherein spring means is carried by said housing and engages said valve member to tend to move said valve member to its closed position.

5. A combination as set forth in claim 1 wherein said fulcrum member comprises a substantially cylindrical rod having opposed ends.

6. A combination as set forth in claim 5 wherein said pin has an opening passing therethrough and telescopically receiving an intermediate portion of said rod whereby the opposed ends of said rod extend beyond opposed sides of said pin.

7. A combination as set forth in claim 6 wherein said intermediate portion of said rod is press-fitted in said opening of said pin to secure the same together.

8. In combination, a housing means having an inlet and an outlet interconnected together by a valve seat, a movable valve member for opening and closing said valve seat, a lever having one end for moving said valve member relative to said valve seat, an axially movable pin carried by said housing means and having one end means fulcruming said lever intermediate the ends of said lever, and manipulator means carried by said housing means and having one end engaging the other end of said pin whereby said manipulator means adjusts the axial position of said pin along its longitudinal axis relative to said housing means, said one end means of said pin including a fulcrum member disposed transversely to said longitudinal axis of said pin and against which said lever engages to fulcrum thereon, said fulcrum member comprising a substantially cylindrical rod having opposed ends, said lever having an intermediate portion thereof engaging said rod only at said opposed ends thereof.

9. A combination as set forth in claim 8 wherein said intermediate portion of said lever has a substantially in- 8 verted U-shaped longitudinal groove extending from one side thereof to the other side thereof.

10. A combination as set forth in claim 9 wherein said intermediate portion of said lever has a substantially inverted V-shaped transverse cross-sectional configuration at the apex of said inverted U-shaped groove whereby only said opposed sides of said lever engage said opposed ends of said rod.

11. A combination as set forth in claim 10 wherein said intermediate portion of said lever has an opening passing therethrough between the opposed sides thereof, said pin having an end projecting through said opening of said lever.

References Cited UNITED STATES PATENTS 2,240,374 4/1941 Newton 236-92 X 3,193,200 7/1965 Willson 23646 3,386,656 6/1968 Bergquist 236-15 WILLIAM E. WAYNER, Primary Examiner U.S. Cl. X.R. 74522; 251234 

